KR900002120B1 - Continuous casting apparatus of twin-drum type - Google Patents

Abstract

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Description

Double Drum Continuous Casting Machine

1 is an explanatory diagram showing a rolling state of solidification angle in a twin roll continuous casting machine.

2 is an axial side view of the twin drum of FIG.

3 to 5 show a twin drum continuous casting machine of an embodiment of the present invention, and a plan view of FIG.

4 is a cross-sectional view in the drum axis direction of the continuous casting machine of FIG.

5 is a side view of the drum shaft of the continuous casting machine of FIG.

Figure 6 is a schematic structural diagram of a twin roller continuous casting machine showing another embodiment of the present invention.

7 is an explanatory view viewed in a direction perpendicular to the roller axis showing the crimping phenomenon of the solidification angle crimp unit in the double roller type continuous casting machine of the present invention.

Fig. 8 is an explanatory view showing the expansion direction of the solidification angle crimp section in the double roller type continuous casting machine.

9 is an enlarged explanatory view of the solidification angle crimping unit shown in FIG.

10 is a characteristic diagram showing the relationship between the position in the solidification angle and the solidification angle temperature in FIG.

11 is a side view of FIG.

* Explanation of symbols for main parts of the drawings

(1), (1 '): Drum (2), (2'): Side dam

(3), (3 '): solidification angle (4): solidification angle crimp

(5): thin plate (6), (6 '): side refractory

(7), (7 '): Metal cold plate (8), (8'): Back plate

(9), (9 '), (29), (29'): spring (10), (10 '): housing

(11): Bearing box (12), (12 '): End of drum body

(28): cooling flow path

The present invention relates to a twin drum type continuous casting machine for continuously manufacturing a thin plate while rotating a drum by storing molten steel between a pair drum and a side dam.

The twin drum type continuous casting machine stores molten steel between two drums as shown in Japanese Patent Laid-Open No. 1983-187244, and also cools and solidifies the molten steel on the two drum surfaces, and drives the two drums in rotation again. By pressing two solidification angles to each other to produce a thin plate continuously.

Because of this structure, solidification at the end of the plate tends to be faster in the manufacturing process of the thin plate than in the center beam of the plate. Next, as shown in FIG. 1, the crimping portion 4 of the narrowest gap between the drums that compresses the solidification angles 3 and 3 'generated on the two drums 1, 1' side during molten steel storage. ) Generates a pressure P for pressing the solidification angles 3 and 3 '.

When the solidification angle is compressed in this manner, pressure P is generated on the drum surface, and at the same time, pressure P _S is also generated on the side, i.e., in the width direction of the plate, as shown in FIG.

That is, as shown in FIG. 2, the side dams 2 and 2 'which hold the molten steel in the width direction of the plate by the pressure P _S at the crimping portion 4 between the pair drums 1 and 1'. The force that opens to the outside acts. This force is excessively solidified at the end of the plate, as can be seen in Japanese Patent Laid-Open No. 1983-187244, and the pressure increases correspondingly.

In general, when casting steel, the temperature of molten steel is about 1550 ° C., so that the side dams 2 and 2 'are fire resistant bricks as shown in FIG. do.

By the way, the pressure P _S generated in the compression section of the drum for crimping the molten steel having a solidification angle is about 200 kg / cm 2 because the temperature of the material with the solidification angle is close to 1350-1400 ° C. Large pressure occurs.

On the other hand, the side dam (2), (2 ') is, but consists of refractory bricks, the strength at high temperatures is was significantly lower, thin plate by the pressure P _S as shown in FIG. 2 in the above FIG. 2 ( 5) is pulled downward and wears rapidly.

When the side compressive force of the side refractory is weakened to reduce the wear, the side dams 2 and 2 'are pushed outward in the width direction of the plate to extend the drums 1, 1' and side dams 2, A gap was formed between (2 '), and molten steel of the molten steel pool leaked out of this gap, and a fin was formed to prevent the realization of the twin drum continuous casting machine.

As a means to solve the above problem, in the example of Japanese Patent Laid-Open No. 1983-187244, it is proposed to use a drum material corresponding to the end of the plate width as a material having low thermal conductivity. Thus, since the thickness of the solidification angle is thin in the place where the thermal conductivity is low, it is considered to be effective in extending the life of the side refractory material even if it is compressed to lower pressure than other central parts.

However, constructing the drum with two materials having different physical properties is complicated in structure and difficult to manufacture, and it is easy to form a gap at the boundary between the two materials, and there is a possibility that molten steel may leak and become impossible to cast. I can't.

In addition, as disclosed in Japanese Patent Laid-Open No. 1983-218358, the side dam is often pressed against the drum side, and is often used to serve as a capacity storage.

In such a usage, as described above, the side dams are made of refractory material, and the drum is made of a metal having excellent cooling property. Therefore, at these two contact surfaces, the refractory material is usually high temperature, and is weak and wears rapidly.

In general, when the production speed of the thin plate is 30 m / min, the refractory wears out in about 1 minute, and the gap is formed in the moving part in contact with the drum, and the molten steel begins to leak, which is problematic in use as a continuous casting machine for mass production.

In addition, the fixed side plate disclosed in Japanese Patent Laid-Open Publication No. 1983-38640, which describes a twin-belt continuous casting machine, has a shape in which the end portion protruding into the molten steel becomes thinner and is made of refractory and a quenching metal part arranged in accordance with the plate width. However, the thickness adjusting roll supports the solidification angle and the static pressure of the molten steel, and is not rolled or crimped, and there is no phenomenon in which the width is widened by rolling. It is enough about mm.

In addition, it is thought that the quenched metal sheet can achieve the object in the vicinity of the thickness adjusting roller.

However, in a twin-drum continuous casting machine suitable for producing a few mm thin plate directly, rolling or pressing the plate immediately after solidification angle formation to the drum is a necessary condition for securing internal quality. It is necessary to find the structure and placement dimensions. In other words, there is a need to solve a new structure that prevents the formation of a structural dimension suitable for rolling width expansion and a gap between the side dam and the drum.

In addition, Japanese Patent Laid-Open No. 1984-21524 discloses a technique for increasing the rotational speed of a double roller when the width of the solidification angle by the double roller exceeds a predetermined amount. JP-A No. 1984-21525 discloses a technique for raising and operating the side dams corresponding to the expansion amount of the width during the solidification angle compression by the double roll. However, in all these known examples, the side dams forming the molten steel pools between the twin rolls are formed of refractory only, and the plate widths formed when the solidification angles formed in the twin rolls of the molten steel are pressed together to secure the internal quality of the thin plates. The large width expansion in the direction does not avoid damage or wear to the side dams. Therefore, in consideration of the protection of the side dams, necessary crimping cannot be performed, thus making it difficult to secure the internal quality of the thin plate.

An object of the present invention is to provide a simple expansion of the width in the plate width direction during the solidification angle compression between the two drums necessary to ensure the internal quality of the sheet, and also to ensure the sealing of the molten steel between the drums The present invention provides a continuous casting machine for twin drums having side dams.

A feature of the present invention is that side dams are disposed at both ends of two rotating drums to form pools of molten steel between the drums and the side dams, and the molten steel in the pools is rotated while the drums are rotated in opposite directions. In a twin drum continuous casting machine which cools and forms a thin plate by pressing together the solidification angle of molten steel formed on the surface side of these drums at the narrowest gap between both drums, the side dam is a refractory for storing molten steel, It consists of a metal cooling plate which supports, so that the said refractory may protrude from a metal cooling plate to a molten steel side, and the lower end part of this refractory exists in the vicinity of the rolling starting point of the molten steel solidification angle located above the narrowest gap part between both drums. It is a twin drum continuous casting machine that excreted the refractory.

A twin drum continuous casting machine of an embodiment of the present invention will be described with reference to FIGS. 3, 4 and 5. The side dam is composed of side plates 6 and 6 'and cooling plates 7 and 7' made of a metal member for supporting the side refractory 6 and 6 '.

The side refractories 6 and 6 'are disposed at a position in which m is moved into the molten steel pool side from the fuselage end faces 12 and 12' of both cylindrical drums 1 and 1 ', and the drum The side shape of the side refractory body becomes the shape according to the drum radius R so that a clearance gap may not generate | occur | produce in the contact part with and is integrally attached to the rapid cooling plates 7 and 7 '. The cooling plates 7 and 7 'are provided with cooling passages 28 and 28' for circulating a cooling fluid. Therefore, the molten steel is pouring in as much as 2m narrow opening width, i.e. the width W ₀ of the molten steel puul for panpok W of the desired sheet. For example, when W = 1000 mm, m = 5-30 mm and W ₀ = 990-940 mm are suitable.

In addition, the side refractory 6, 6 'is because the purpose of storing stably a molten steel, the the lower end thereof is positioned on the upper side as h ₁ eseo Figure 4 line AA passing through the narrowest gap of the two drums as shown in Do it. That is, by crimping the solidification angles 3 and 3 'by making h ₁ larger than the length L of the crimping portion 4 reaching the narrowest gap portion at the start of rolling of the solidification angles 3 and 3'. The side refractories 6 and 6 'do not receive a force while the width spreads out. On the other hand, the cooling plates 7 and 7 'are arranged in a pressing state with respect to the crimping portions 4 of the solidification angles 3 and 3'. The springs 9 and 9 'are pressurized to the 12 and 12'. Therefore, as shown in FIG. 3 and FIG. 4, the cooling plates 7 and 7 'are made to be in close contact with the fuselage end faces of the drums 1 and 1'. The springs 9 and 9 ', which are the pressurizing devices described above, need to be adjusted so as not to increase the pressure pressure against the drum thermal expansion during casting, but any type of liquid pressure, cushioning material, etc. may be used as well as the spring. The springs 9, 9 ′ are supported by the back plates 8, 8 ′, and the back plates 8 in the housings 10, 10 ′ supporting the drum bearing boxes 11. And 8 'are attached.

In addition, the vertical lengths of the metal cold plates 7 and 7 'need to be aligned with the drum body end faces 12 and 12' so that the hot water does not leak even when the molten steel surface is at the lower side at the start of casting. Even in the steady state shown in FIG. 4, in the case where the molten steel leaks from the end of the plate, it supports the same and also has a function of cooling and solidifying the lower ends of the cooling plates 7 and 7 'in the vertical direction. The location is suitably extended and excreted from the line AA through the narrowest gaps of both drums to the lower h ₂ (h ₂ = 0-100 mm).

The side refractories 6 and 6 'are preferably not placed in the crimping portion 4 for crimping the solidification angle formed toward both drums, but the expansion of the crimping portion of the solidification angle is shown in FIG. Since the taper is gradually expanded, at least the taper corresponding to the amount of expansion of the width is formed in the vertical lower end portion of the side refractory parts 6 and 6 'in advance, and the side refractory parts 6 and 6' are formed in the crimping part 4. ), The same effect can be expected. However, when the plate thickness to be cast is as thin as 2-3 mm, the side refractory materials 6 and 6 'must also be made thin, and since it is easy to be destroyed, it is not practically good.

Therefore, the distance h ₁ from the line segment AA, which is the narrowest gap portion of both drums, to the excrement position of the vertical lower end portions of the side refractory parts 6 and 6 'is equal to or longer than the rolling start point L that compresses the molten steel solidification angle. The cooling plates 7 and 7 'made of metal containing the cooling flow paths 28 and 28' which support this refractory are further set backward, and are placed further in the plate width direction upward direction of this thin plate, and this cooling plate It is practical to configure (7) and (7 ') to the shape which contacts the fuselage end surface of both drums (1) and (1').

Next, the relationship between the lower end positions of the side refractory materials 6 and 6 'and the rolling start point which crimp | bonds the molten steel solidification angle between both drums is demonstrated in detail.

As shown in FIG. 7, the detailed structure of the crimping portion 4 which compresses the solidification angles is different from the liquidus line T _L of the molten steel and the solidus line T _S forming the solidification angle. It is effective to compress in the vicinity of the intersection of the drum rotation, i.e., near the one point and the S point.

As a reason, when the S point is located above the narrowest gap portion of both drums, the thin plate after solidification is rolled, and an excessive pressing force is required, resulting in an enlargement of the apparatus and economically disadvantageous. If the one-point S point is below the narrowest gap between the two drums, there is a defect that molten steel that does not solidify comes out or the expansion of the plate occurs due to the static pressure of the molten steel, making continuous casting difficult. .

In the above embodiment according to the present invention, since the reaction solidification angles 3 and 3 'in the middle of T _L and T _S are pressed together, the deformation resistance is very small (1-2 kg / mm 2). The size of the drum pressurizing device and the driving device can be reduced in size, and the shape of the cast sheet is less likely to be deteriorated since it is not necessary to press hardly. In addition, since the pressing force is small, when the width direction of the solidification angle becomes uneven (particularly, the end of the plate is thick), the thick part is particularly rolled, so that this part extends in the plate length direction and causes deterioration of the plate shape. However, in the case of pressing lightly, the same thing as described above is reduced (when the coagulation angle of the plate edge is thick, the protrusion is extended when pressing strongly, but in case of pressing slightly, the stretching is greatly reduced).

In addition, it has already been confirmed that the internal quality of the plate due to the reaction high pressure is inferior to the post-solidification rolling method.

Since the compression of the non-solidified portion leads to the expansion of the plate width due to the pressurization, it is as described above that the side refractory material is placed in this part, causing damage and abrasion, thereby making it impractical. Therefore, in the continuous casting machine of the present invention, the lower end of the side dam is disposed at a position vertically higher than the crimp start position L, and the appropriate positioning of L is expressed by the following equation.

L ≒ R (2X ₀ -t) ≒ 2 to 4 R

For example, the temperature of the solidification angle of SUS304 stainless steel, which is a molten steel material, as shown in FIG. When t = 5mm is obtained, X ₀ = 4.5mm

L ≒ 400 × (2 × 4.5-5) = 40 mm

The lower end position D = 40 + α = 50-60mm of a side dam is the most suitable. And this corresponds to L ≒ 2-4R. Next, the protruding amounts (allowing the amount of expansion of the width during solidification angle compression) as the molten steel side of the side refractory materials 6 and 6 'will be described.

As shown in FIG. 8, during compression, the reaction elevation is pushed upward and outward. The amount pushed out in each direction depends on the flow resistance of the solidification interface T _S (subscript), but the actual solidification interface has some ups and downs as shown in FIG. 9, and varies depending on the cooling conditions and the material. During crimping in such a state, the plate width center portion flows upward with less flow resistance, and the plate edge portion flows outside the plate width. Therefore, the leakage amount n in the plate width direction is mainly related to the plate thickness of the plate. Small amount was confirmed through the experiment, and approximately n = (0.2-0.5), t.

For example, when plate | board thickness t = 5 mm, it is about n = 1-2 mm. Therefore, the plate width direction protrusion amount m of the side refractory materials 6 and 6 'should be made slightly larger than the maximum value of n, and when producing t-3-6 mm normally, a favorable product about m_t will be obtained.

In summary, in the embodiment of the present invention, the side of the plate end as a means for delaying the start of solidification in order to eliminate leaking to the side at the drum end when the bending angle compression is performed at the narrowest gap portion of the double drum. The refractory is placed inside the side of the drum with a structure that makes contact with the outer circumferential surface of both drums without gaps, and furthermore, no refractory is placed on the solidification angle compression equivalent portion. In the crimping section, a cooling plate is arranged so as to be located outward from the side refractory, and is compressed and disposed on the drum body end surface.

That is, in order to start cooling by delaying the force P _S which leaks out in the width direction by crimping | compression-bonding, a width direction step | step is provided in a side dam.

In addition, the portion in contact with the drum body end face is pressed against a metal member resistant to contact wear different from the refractory, and the refractory is attached to the metal member.

Bearing metals such as bronze and aluminum bronze are used for the metal member, and lubricating oil is supplied to the contact portion with the drum body end surface, thereby greatly reducing the contact wear between the two.

As described above, the twin drum type continuous casting machine according to the embodiment of the present invention is a refractory inserted into the molten pool firstly with no gap between the two drums, and the member supporting the refractory includes Is a metal member which can move other slides, and is pressed against the side of the drum to have both slide moving functions.

Secondly, the lower end portion of the refractory is disposed so as to be located at a portion corresponding to the solidification angle crimp portion of the double drum or slightly higher, and the metal member supporting the refractory is disposed in a stepped shape, and this is at the short side of the thin plate. Cool the molten steel.

Next, another Example of this invention is described. 6 and 11 show an embodiment in which the side dam of the present invention is applied to a twin drum type continuous casting machine having a structure in which a drum can move in an axial direction in response to a change in plate width.

In the drawings, since the basic configuration of the apparatus is the same as in the previous embodiment, description is omitted and only different portions will be described.

By moving the paired drums 1 and 1 'in the drum axial direction in the directions of the arrows X and X', the casting range can be changed so that the desired plate width W ₀ is obtained (in the axial movement of the drum Not shown).

In such a twin drum continuous casting machine, side refractory materials 6 and 6 'for storing molten steel are inserted between the pair drums 1 and 1'. The cooling plates 27 and 27 ', which are pressed onto the fuselage surfaces of the drums 1 and 1' by the springs 29 and 29 ', which are other pressing devices, are cooled to be pressed only on one drum surface. The side surface shape of the board is formed in the shape of a curvature surface suitable for the drum outer surface.

By constructing the side dams in this way, the same effects as those of the present invention can be obtained also for the twin drum continuous casting machine of the variable plate width.

According to the embodiment of the present invention described above, the possibility of side dams is divided into corresponding ones for the molten steel storage part and the crimping part, respectively, so that the side refractory of the molten steel storage part corresponds to the enlargement amount of the width of the solidification angle that is inside the desired plate width. It is a molten steel side, which is placed above the starting point of solidification angle to secure the coagulation delay of the end of the plate, and the side dam of the crimp part is a cooling plate, which is arranged in the desired plate width, thus expanding the width at the time of crimping. Even if this occurs, the expansion force of the width due to the solidification angle compression on the cooling plate does not occur, and thus the side refractory breakage and local wear can be prevented.

In addition, stable continuous casting operation without leaking molten steel can be realized even when abnormality occurs when the molten steel is present in the crimping portion between the double rollers as in the start of casting.

According to the present invention, the expansion of the width in the plate width direction during the solidification angle compression between the two drums required to secure the internal quality of the thin plate is allowed, and the sealing of the molten steel between the drum and the drum can be reliably ensured. It is effective to realize a twin drum type continuous casting machine provided with a side dam having a simple structure.

Claims (6)

Side dams are disposed at both ends of the two rotating drums to form molten steel pools between the drums and the side dams, and the molten steels in the pools are cooled by rotating the drums in opposite directions. In the twin drum type continuous casting machine which presses the solidification angle of molten steel formed in the surface side of these drums at the narrowest gap part between both drums, and manufactures a thin plate, The said side dam is a refractory which stores molten steel, It consists of a rapid cooling plate which supports a refractory, and protrudes the said refractory to a molten steel side from a metal cooling plate, and near the rolling start point of the molten steel solidification angle in which the lower end part of this refractory is located above the narrowest gap part between both drums. A twin drum continuous casting machine, characterized in that the refractory is excreted to be present in. The twin drum type continuous casting machine according to claim 1, wherein the side dam is provided with a pressurizing device for pressing the metal cooling plate to the body end face of the drum. 3. The drum according to claim 1 or 2, wherein the drum is configured to be movable in the drum axis direction, and the side dams are arranged to contact the metal cooling plate while slidingly moving with respect to at least one drum body portion. A twin drum type continuous casting machine, characterized by comprising a second pressurizing device for pressing a metal cooling plate to a drum body part. 4. The twin drum continuous casting machine according to claim 3, wherein the drum is configured to be movable in a drum axial direction. The twin drum type continuous casting machine according to claim 1, wherein the amount of protrusion of the refractory constituting the side dam is formed to be equal to the thickness of the thin plate to be manufactured. The position of the lower end part of the refractory part which comprises the said side dam with respect to the narrowest gap part between both drums was set to the range of 2-4 times the square root of a drum radius. Double drum continuous casting machine.

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